Railway tie



Sept. 7 1926.

W. H. KOBB RAILWAY TIE Filed Dec. 21, 1925 3 Sheets-Sheet 1 y ATTORNEYS Sept. 7 1926.

w. H. KoBBE RAILWAY TIE 1925 3 Sheets-Sheet 2 mi YQ .QW MQ Y Filed DSC. 2l

INVENTOR Sept. 7 1926.

w. H. KOBB RAILWAY TIE 1925 3 Sheets-Sheet 3 Filed Deo. 21l

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I Patented Sept. y7, 1926.

sTATEs 1,599,136 lPATEisrr OFFICE. 9

wvIIQLLANJsiTornrANxoBB, or NEW Yonx, N. Y., AssiGNon To TnxAs GULF son [Papua coiuANY, or BAY CITY, TExAs, A conronATIoN or TEXAS.

RAILWAY T111.V

Application illed December 21, 1925. Serial In. 76,587. Y

*The present `invention relates to railway Aties or sleepers `used in railway construction,

andhas vfor its object the provision of an improved railway tie. IAlthough wooden ties have been used almost exclusively since the beginning of railways in this country, there has been a gradual chan e inthe kind of wood used.4 For-` merly on y the best rade of oak was eni- 10 plo ed but with the a vancing cost of wood, an the scarcityA of oak, many other species are nw bein utilized.-r Wood preservation has proved a 'vantageous andsouthern pine, cypress and other ies are now bein made 15 into ties and trente `with creosote an other materials. However, the increasing scarcity of the various woods now available that are suitable for ties makesfthenecessity for substitu'tev materials vmore and more apparent', Wood sses no particular quality which inalEes it superior to other materials, but it is cheaper, andheretofore no substitute has, been found whichwill successfully com te economically with a wooden tie, particularly when" treated inaccordance with present dayy ractiee.

A resilient bed, suchvas is obtained by the use of wooden `4ties, `was at one time thou ht essential but the advocates of the 80 rigi type of track construction ein laying concrete or metal ties have proved t' at the advantages kof the .resilient tie are out wei hed by 'the many advantages of the rigi t of, construction.

eneral yuse were it not for the fact that the 'fe of a concrete or steel tie asnow made is not sufficiently in excess of that of a treated Awooden tie of high lQuality to compensate 0 Y for the difference inV rst cost.

An idea of the industrial importance of the problem is indicated by the following fi ires which re resent the a roxmate tie gl P Pp total quantity absorbed. A readil impreg-` 4requirements per year of various countries: 5 Germany. 5,600,000 y Great Britain 5,800,000 France-.. 5,400,000 Italy- 1,600,000 Switzerland 300,000 l HollancL... 5a--.. 280,000 ISjpa,i1i... ....L.; l...1.a 1,500,000 nited States-..j....; 30,000,000

The improved railway t'e of my present invention costs 4somewhat more than either n Concrete.v or. metal ties would therefore come into more l wood or concrete but theim roved vproperties which it possesses more t an justify the increased first cost. I have discovered that sulphur, when appropriatel associated therewith imparts certain qua ities to railway ties which rendersties made of manyl substitute materials far superior to wooden 'tiesas commonly made and treated, and in addition,v when associated with railway ties `of inferiorspecies of wood makes thein the equal of ties made of hard, durable species. Thus, according to my invention, woods which have heretofore been unsuited for use as railway ties may now be used.

It is to be understood, moreover, that the term substitute materials isintended to include, not only concrete, but any substitute for Wooden railway ties, and the invention hence involves the provision of a sulphur-containing railway tie. In carrying out the invention, the railway tie which, let us say, is constructed in this iiistance of wood, is immersed in and held beneath the surface cfa bath of molten sulphur which is maintained at a temperature referably of about 140 to'150 C. for the 5 vor 6 hours,lor until the evidence of dmoisture hasy disappeared. It is then desirable to allow the .temperature of the bath to drop to about 120 or 125 C. for the remainder of the time or 4 to 5 hours, when the tie is' removed. The extent of penetration is generally evidenced bv the buoyancy of the tie in the sulphur bath and complete cestion of bubbling. A fully im regnated w i e sul bur, -and' will of course sink in water.

he period of immersion depends upon-A many {actora-but inA eneral I leave the ties v made of various w sin the bath :for not less than.,10 or 12 hours and insome cases double this ytime has little eiect upon the nated tie may require only 4 or 5` ours, but in all investigations -to date an e'ort has been made tp secure maximum impregnation irrespective of the time element in order to determinejust what woods may be treated by -jtlfesimple open tank immersion method r without the application of vacuum or pressure, and theportion of the tree best adapted for this method of impreation.

` In'my investigations, w

ioo-

te pim?, sugar 0r Western white pine, red and white pialmetto, so-called soft and hard California redwood,

poplar, cypress, white wood (L'erodendron.

tulzpifem),'hard maple, beech, birch, red oak, white spruce, cedar and other species have been impregnated with sulphur. These include the various types of woody growth such as hardwood o r broadleaved species,

' soft woods or conifers,vand the palms.

The use of vacuum and/or pressure expedites the impregnation process, but in some cases there is not sufficient increase in the quantity` of sulphur entering the wood to justify the expense of its employment.

Certain species of wood absorb approximately v-as much sulphur by the open tank -treatment as would enter the wood under vacuum and pressure. Certain species which are very resistant to impregnation by open tank treatment are equally difiicult to imlpregnate with vacuum and pressure. In order to secure the most thorough impregnation it is important thatl the wood be seasoned vor properly dried before the ties are given the sulphur treatment because the presence of moisture inhibits penetration of sulphur and when in excess, prevents -the entry of practicaly)I any sulphur. be explained by e fact-that it is difficult for the sulphur to enter the tra'cheids, pores or resin ducts while moisture isvbeing driven off in the form of steam, and in addition, the conversion o f water into steam requires a cert-ain amount of heat and has a tendency to lower the temperature of the woody mass, with the constant cooling of the molten sulphur in immediate contact with the wood.

I have. found that dry white pine, especially the sapwood, absorbs several times'its ow'n weight of sulphur and when impregnated, consists of as much as 60% to 70% by kweight of sulphur based upon the inal Weight' of the treated Wood. California redwood absorbs approximately its own weight of sulphur, while Florida palmetto absorbs about the same as white pine, or' from 60% to 70%, but requires a much longer` period of immersion. The other species of wood mentioned in this specification absorbanywhere from about 5% or 6% up to about 50% or' more sulphur, depending upon the conditions and structure ofthe wood. v f

The effect of the association of sulphur with the wooden railway tie is to indurate andstrengthen it.- Under Acompression parallel to the grain untreated pine withstood under test a maximum load of 3,500 pounds per square inch, whereas pine impregnated with sulphur by the open tank method for a period of about 12 hours, or in other words, impregnated to` the maximum extent, required 5,800 pounds per square inch to bring about the failure. The sulphur treated wooden tie is also much more resistant to This may impact and is several times harder than the untreated. For example, if the hardness of untreated hemlock is taken as 100, sulphur treated hemlock was found under test to have a hardness of from about 300 to 350.

As is well known, California redwood will last almost indefinitely in the ground, but it cannot be used for railroad ties under heavy 'traiiic becausethe rails, either with or without tie plates, cut int-o and destroy the tie long before the centerl portion has deteriorated in any way. By treating the tie with sulphur according to my invention it is possible to soindurate or harden the wood as toadmirably adapt it for use as a railway tie. Such a tie may be completely impregnated with sulphur if desired but a partial impregnation suflicient to harden the Wood in the region of the surface of the tie, say for example to a depth' of about 1 is suiiicient. This hardening of the surface greatly .reduces the rate of cutting by therails and a tie is tlius'produced which is extraordinarily serviceable. If desired, only the ends or the wearing surfaces of the tie need be impregnated with sulphur.

Other woods are rendered, by the process of the invent-ion much more durable for use as railway ties because of the preservative qualities imparted by the sulphur as well as the increase in hardness and strength resulting from the sulphur treatment. In order to bring about wood rot the presence of heat, moisture and oxygen are necessary, and sulphur excludes at least two of these agencies. In other words, the sulphur preserves the wood physically rather than by chemical means and isolates it from the action of Wood rot fungi. Therefore, although not in itself toxic, sulphur acts as a preservative ofthe wood in that it excludes and'prevents the entry and action of the destructive agencies.

The extent of impregnation desirablewillV also depend upon' what physical properties it is desired to improve. Thus if merely an increase in resistance to mechanical abrasion and wear .is desired, a mere surface impregnation is all that is required. On the other hand, although the surface impregnation will increase the strength of the tie to a certain extent depending upon the. depth to which it is carried, if a maximum increase in strength -is desired, as much sulphur as is possible should be allowed to congeal within the pores'of the tie.

Another advantage in the sulphur treated tie is to be found in the fact that it will hold spikes much better than the untreated ties. A practical consideration ink connection with the invention is the fact thatl the impregnation of the ties with sulphur may be carried out in the usual creosoting cylinders now extensively employed for injecting creosote oil into railway ties.r

Sulphur being an insoluble solid at ordinary temperatures, the eilect of my treatment is different from that brought about by the use of any other impregnant. Creosote does not change its form after entering the Wood, nor do the various waxes such as Montan wax, or the metallic salts similarly employed unless such salts enter the wood in the form of a solution. On the other hand, my treatment injects an elemental fluid into the y-Wood which becomes a ciystal` line solid and this change is so rapid that the Surface pores are almost immediately closed through solidi'tication of the sulphur and kick-back such as occurs with other materials, is prevented. For example, when creosote oilis forced into wood under pressure, and this pressure is removed, a portion of the oil exudes from the wood because there is nothing to counteract the internal pressures; In my process, the rapid solidification of the sulphur on the surface and articularly at the'ends of the treated woo immediately seals the pores and prevents the loss of the molten sulphur contained within the Woody structure.

. The sulphur treatment of the. invention is particularl applicable tol concrete ties which hereto ore have notbeen sufficiently strong to Awithstand traic conditions, even thoughheavily reinforced with metal.

y Ultimate failure in an untreated concrete tie is brought about through mechanical and chemical agencies of a destructive nature. The impact of the rail under traffic, gradual movement and creeping of the rail andrail fastenings and the absorption and freezing of water within the tie structure are the more important destructive agencies of a mechanical nature., In chemical processes play a part in the destruction of an ordinary concrete tie. Tie plates, rail astenings and the reinforcing metal oxidize and occupy an increased volurne which is destructive to the ties. Corrosive soilsor ballast material which contain sulphates are also veryy destructive to ordina ry concrete.

I have discovered that by impregnating concrete ties with sulphur, both the tensile and compressive strength are increased from.

able concrete mlxture'such for example as' Portland cement, water and aggregate maaddition,

terial such as crushed rock and/or sand and /or gravel, are immersed in a bath of moltenmsulphur which is maintained at a temperatureof from 140 to 15()o C. for a number of hours, as in the case of the impregnation of wood. After the moisture appears to have been driven ofi', the temperature of the bathis then reduced to in the neighborhood of 120 to 125 C. for a further number of hours.l

The period of immersion at the higher temperature as well asthe total period of ii'nmersion depends,` as in the case of the impregnation of Wood, upon many factors, such for example as the penetrability of the concrete mixture, and the extent of impregnation desired. It a material increase in strength is looked for, the ties should be impregnated until the sulphur has pene-V trated to a considerable depth, if not throughout the entire mass of the concrete` but it' it is only desired to. render the ties resistant to the destructive agencies to which they are subjectedvin service, a relativel i shallow impregnation, .say for examp e from 1/2 tol 1" is all that is necessary. This partial impregnation is obtained in a correspondingly shorter length of time. The concrete ties may be impregnated with 'sulphur as soon as the concrete has set sutlicientl lto allow the ties to be handled Without reaka e, or if desired, the

concrete may be allowe to set until it has reached its. maximum strength and then given the sulphur treatment. Hence, either concrete ties which have just been manufactured, or those which are ready to'y be placed in service, may be advantageously treated with sulphur.

The .remarkable increase in tensile strength resulting from the sulphur treatment of the invention has been shown by a series of tensile strength tests which have been conducted for the purpose of comparing untreated and sulphur-impregnated concrete. In carrying out these tests, three sets of tensile briquets were prepared. AOne of these sets was impregnated with sulphur and tested after a period of 7 days. second set was impregnated and tested after aperiod of 28 days, andthe third set after a. period l of three months, In each ycase unimpregnated control specimens, that is, specimens made of the same proportionate mixture of Portland cement and sand, were broken at the same time with the sulphurimpregnated specimens.

The attached drawings illustrate in detail the remarkable increase in strength impartedV 'to the concrete by the association therewith of sulphur. In these drawings l Fig. 1 is a diagrammatic representation illustrating the results of these tests as shown by the. test specimens'which were treated and broken at the age of 7 days;

Fig. 2 is a similar strength diagram of specimens treated and broken at the age of 28 days; and

Fig. 3 is a similar diagram of specimens treated and broken at the age of Vthree months.

In each of these figures, curve A shows the tensile strength in pounds per square inch of plain or unimpregnated specimens of concrete containing various percenta es of Portland cement. Curve B of each gure Ashows similarly the tensile strength of correspondingly similar specimens of concrete completely impregnated with sulphur.

In addition to railway ties made of concrete of the usual constituents as just described, railway ties may be made of various other mixtures of materials and then impregnated with sulphur in accordance with the invention. Thus, for example, ties made of a sand-lime mixture such as is now employed for the manufacture of sand-lime brick, or made of a cinder-Portland cement mixture, when impregnated with sulphur may be used in many instances in place of the concrete tie or the wooden tie. In fact, railway ties may be made in accordance with my present invention from a large number ofl materials, or combinations of materials which are capable of absorbing molten sulphur and which can be impregnated with molten sulphur. Thus railwa ties may be made according to the invention from sulphur-absorbing materials in which the congealed molten sulphur acts as a crystalline binding agent imparting the requisite degree of additional strength and imperviousness to result in` a satisfactory and economical tie.

I claim:

1.V As an article of manufacture, a railway tie made of relatively soft wood impregnated in part at least with sulphur.

2. As an article of manufacture, a railway tie made of redwood impregnated in part at least with sulphur.

In testimony whereof I ax my signature.

WILLIAM HOFFMAN vKoBB. 

